<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script type="text/javascript" >
        var f1 = function () {
            alert("无参函数");
        }
        var f2 = function (a,b){

            alert("有参函数=>" + a + "有参函数=>" + b );
        }
        //有返回的函数
        var f3 = function (){

            var a =3;
            var b = 7;
            return a + b;
        }
    </script>
</head>
<body>

</body>
</html>